This is already available for iOS

https://itunes.apple.com/us/app/lekh-diagram/id576124115?mt=...

OmniGraffle[1] is great and has been around since the iPad’s launch in April of 2010. It’s a mature app, it has had many updates[2].

[1] http://www.omnigroup.com/products/omnigraffle-ipad/

[2] http://www.omnigroup.com/products/omnigraffle-ipad/download/...

Looks like it was an iOS app first.

http://blog.avabodh.com/2013/03/lekh-diagram-now-available-f...